^Well, Nero didn't blame the Federation for deliberate destruction, but for betraying its promise to save Romulus. Arguably that sense of betrayal would be more strongly felt toward a nation that the Romulans had grown to trust as a friendly power. "You said you'd help us, but you didn't really care, did you?" Nero probably won't be the only Romulan who feels that way. But probably other Romulans won't be able to get their hands on supplies of red matter and thus won't be able to act out their anger so destructively. And the surviving Romulan government would probably be more inclined to accept whatever aid they can get, including Federation aid (though with the Pact there to come to their assistance, they may not feel they need UFP help).